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SP495
Quad Differential RS-485 Transceiver
s Pinout for SCSI Interface s Meets EIA-485 Standard for Multipoint Bus Transmission s +5V-Only Power Supply Required s Receiver Fail-Safe Mode s Low Power BiCMOS Technology s Glitch-Free Power-Up/Down s Available in 20-Pin Plastic SOIC s Pin Compatible with DS36954
DESCRIPTION... The SP495 is a quad differential line driver/receiver meeting both RS-485 and RS-422 standards at data rates beyond 10Mbps. The SP495 features three half-duplex transceivers suitable for data bus connections and a fourth full-duplex transceiver with independent driver, receiver enables. Ideal for use as a control bus transceiver. A complete SCSI initiator or target interface can be implemented using five SP495s. Propagation Delay Skew is tightly specified to aid in parallel interface designs. The SP495 is available in a 20-pin plastic SOIC package for operation over the commercial and industrial temperature ranges. For PLCC availability, please consult factory.
OA1 OB1 20 19
OA2 OB2 18 17
SP495V
16
cc OA3 OB3 15 14 13
OA4 OB4 12
R1 D1 D2
R2 D3
R3 D4
R4
2
1
3
4
11 GND
6
5
8
9
7
10
DR1 DE1/RE1
DR2 DE2/ RE2
DR3 DE3/ RE3
DI4 DE4
RO4 RE4
SP495
Quad Differential RS-485 Transceiver
(c) Copyright 2000 Sipex Corporation
1
ABSOLUTE MAXIMUM RATINGS
These are stress ratings only and functional operation of the device at these ratings or any other above those indicated in the operation sections of the specifications below is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability. VCC............................................................................................................................+7V Input Voltages Logic...................................................-0.5V to (VCC+0.5V) Drivers................................................-0.5V to (VCC+0.5V) Receivers....................................................................15V Output Voltages Logic...................................................-0.5V to (VCC+0.5V) Drivers...........................................................-8V to 12.5V Receivers...........................................-0.5V to (VCC+0.5V) Storage Temperature....................................................-65C to +150C Power Dissipation.....................................................................1000mW
SPECIFICATIONS
TMIN to TMAX and VCC = 5V 5% unless otherwise noted.
PARAMETERS DRIVER DC Characteristics Differential Output Voltage Differential Output Voltage Differential Output Voltage Change in Magnitude of Driver Differential Output Voltage for Complimentary States Driver Common-Mode Output Voltage Input High Voltage Input Low Voltage Input Current Driver Short-Circuit Current VOUT = HIGH VOUT = LOW DRIVER AC Characteristics Maximum Driver Data Rate Driver Input to Output Driver Input to Output Driver Skew Driver Rise or Fall Time Driver Enable to Output HIGH Driver Enable to Output LOW Driver Disable Time from LOW Driver Disable Time from HIGH RECEIVER DC Characteristics Differential Input Threshold Input Hysteresis Output Voltage HIGH
MIN.
TYP.
MAX.
UNITS
CONDITIONS
GND 2 1.5
VCC VCC VCC
Volts Volts Volts
Unloaded; R = ; see Figure 1 With Load; R = 50; (RS-422); see Figure 1 With Load; R = 27; (RS-485); see Figure 1
0.2 3 2.0 0.8 10 250 250
Volts Volts Volts Volts A mA mA
R = 27 or R = 50; see Figure 1 R = 27 or R = 50; see Figure 1 Applies to DRx, DEx/ REx Applies to DRx, DEx/ REx Applies to DRx, DEx/ REx -7V VO 10V -7V VO 10V
10 20 20
30 30 10
60 60
Mbps ns ns ns
RDIFF = 54, CL1 = CL2 = 100pF tPLH; RDIFF = 54, CL1 = CL2 = 100pF; see Figures 3 and 6 tPHL; RDIFF = 54, CL1 = CL2 = 100pF; see Figures 3 and 6 see Figures 3 and 6 From 10% to 90%; RDIFF = 54, CL1 = CL2 = 100pF; see Figures 3 and 6 CL1 = CL2 = 100pF; see Figures 4 and 7; S2 closed CL1 = CL2 = 100pF; see Figures 4 and 7; S1 closed CL1 = CL2 = 15pF; see Figures 4 and 7; S1 closed CL1 = CL2 = 15pF; see Figures 4 and 7; S2 closed -7V VCM 12V VCM = 0V IO = -4mA, VID = +200mV
(c) Copyright 2000 Sipex Corporation
3
15 40 40 40 40
40 70 70 70 70
ns ns ns ns ns
-0.2 70 3.5
+0.2
Volts mV Volts
SP495
Quad Differential RS-485 Transceiver
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SPECIFICATIONS (continued)
TMIN to TMAX and VCC = 5V 5% unless otherwise noted.
PARAMETERS RECEIVER DC Characteristics Output Voltage LOW Three State (high impedance) Output Current Input Resistance Input Current (A, B); VIN = 12V Input Current (A, B); VIN = -7V Short-Circuit Current RECEIVER AC Characteristics Maximum Data Rate Receiver Input to Output Receiver Input to Output Diff. Receiver Skew ItPLH-tPHLI
MIN.
TYP.
MAX.
UNITS
CONDITIONS
0.4 12 0.5 15 10 1.0 -0.8 85
Volts A k mA mA mA
IO = +4mA, VID = -200mV 0.4V VO 2.4V; DEx/ REx = 5V -7V VCM 12V DE = 0V, VCC = 0V or 5.25V, VIN = 12V DE = 0V, VCC = 0V or 5.25V, VIN = -7V 0V VO VCC
10 60 60 13 45 45 45 45 70 70 70 70 +5.25 5 200 200
Mbps ns ns ns ns ns ns ns Volts mA
DEx/ REx = 0V tPLH; RDIFF = 54, CL1 = CL2 = 100pF; Figures 3 & 8 tPHL; RDIFF = 54, CL1 = CL2 = 100pF; Figures 3 & 8 RDIFF = 54; CL1 = CL2 = 100pF;
Figures 3 & 8
Receiver Enable to Output LOW Receiver Enable to Output HIGH Receiver Disable from LOW Receiver Disable from HIGH POWER REQUIREMENTS Supply Voltage +4.75 Supply Current ENVIRONMENTAL AND MECHANICAL Operating Temperature Commercial (_C_) Industrial (_E_) Storage Temperature Package Plastic LCC (_L)
A R VOD R B VOC
CRL = 15pF; Figures 2 and 9; S1 closed CRL = 15pF; Figures 2 and 9; S2 closed CRL = 15pF; Figures 2 and 9; S1 closed CRL = 15pF; Figures 2 and 9; S2 closed
2
DEx/ REx, DRx = 0V or VCC
0 -40 -65
+70 +85 +150
C C C
Receiver Output CRL
Test Point S1 1k S2
1k VCC
Figure 1. Driver DC Test Load Circuit
3V DE DI A B CL2 RDIFF CL1 A RO B 15pF
Figure 2. Receiver Timing Test Load Circuit
Output Under Test
500 CL
S1
VCC
S2
Figure 3. Driver/Receiver Timing Test Circuit
Figure 4. Driver Timing Test Load #2 Circuit
SP495
Quad Differential RS-485 Transceiver
(c) Copyright 2000 Sipex Corporation
3
+3V DI 0V DRIVER OUTPUT B A
f = 1MHz; tR < 10ns; tF < 10ns 1.5V tPLH VO 1/2VO tSKEW tPHL 1.5V tPLH 1/2VO tSKEW
DIFFERENTIAL VO+ OUTPUT 0V VA - VB VO-
Figure 6. Driver Propagation Delays
tR
tF
+3V DE 0V 5V A, B VOL VOH A, B 0V
f = 1MHz; tR < 10ns; tF < 10ns 1.5V tZL 2.3V Output normally LOW 1.5V tLZ 0.5V 0.5V tHZ
2.3V tZH
Output normally HIGH
Figure 7. Driver Enable and Disable Times
V0D2+ A-B V0D2- VOH R VOL tPHL
f = 1MHz; tR 10ns; tF 10ns 0V INPUT 0V
1.5V
OUTPUT tPHL
1.5V
Figure 8. Receiver Propagation Delays
SP495
Quad Differential RS-485 Transceiver
(c) Copyright 2000 Sipex Corporation
4
+3V RE 0V 5V R VIL VIH R 0V 1.5V tZH Output normally HIGH 1.5V Output normally LOW 0.5V 0.5V tHZ 1.5V f = 1MHz; t < 10ns; t < 10ns R F tZL 1.5V tLZ
Figure 9. Receiver Enable and Disable Times
DESCRIPTION General Description... The SP495 is a quad differential transceiver that meets the requirements of RS-485, RS-422, and differential SCSI at data rates to beyond 10Mbps. Fabricated with a proprietary Sipex BiCMOS process, the SP495 requires only a fraction of the power of older bipolar designs. The SP495 features three half-duplex transceivers suitable for data bus connections and a fourth full-duplex transceiver with independent enables ideal for use as a control bus transceiver. A complete SCSI initiator or target interface can be implemented using five SP495s. The RS-485 standard is ideal for multi-drop applications and for long-distance interfaces. RS-485 allows up to 32 drivers and 32 receivers to be connected to a single data bus, making it an ideal choice for multi-drop applications. Since the cabling can be as long as 4,000 feet, RS-485 transceivers are specified for operation with a wide (-7V to +12V) common mode range to accommodate ground potential differences. Because RS-485 is a low impedance differential interface, data is virtually immune to noise in the transmission line. Drivers... The differential drivers for the SP495 have typical output voltage swings (no load) of 0 to +5Volts. With loading to the RS-485 specification (54), drivers must maintain outputs greater than 1.5V.
SP495
The three half-duplex drivers of the SP495 have independent Driver Enable control lines which are active HIGH. A logic HIGH on DEx (pins 1, 4, or 5 of the SP495) will enable the addressed differential driver output. A logic LOW on DEx will tri-state the driver output and enable the receiver. The fourth driver is controlled by its own DE4 Enable line and can be used in half duplex or full-duplex modes. Receivers... The differential receivers for the SP495 have an input sensitivity of 200mV. Input impedance is typically 15k (12k minimum). A wide common mode range of -7V to +12V allows for large ground potential differences between widely separated systems. These receivers are equipped with a fail-safe feature which guarantees that the receiver output will be in a HIGH state when the input is left unconnected (note: this feature operates with floating inputs, not terminated inputs). Like the half-duplex drivers, the three half-duplex receivers of the SP495 have independent Receiver Enable control lines which are active LOW. A logic LOW on REx (pins 1, 4, or 5 of the SP495) enables the differential receivers. A logic HIGH on REx tri-states the receivers. The fourth receiver is controlled by its own RE4 Enable line and can be used in half-duplex or full-duplex modes.
Quad Differential RS-485 Transceiver
(c) Copyright 2000 Sipex Corporation
5
ORDERING INFORMATION
Model Temperature Range Package SP495CT. ......................................................... 0C to +70C ...................................................... 20-Pin SOIC SP495ET ........................................................ -40C to +85C .................................................... 20-Pin SOIC
For PLCC availability, please consult factory.
Corporation
SIGNAL PROCESSING EXCELLENCE
Sipex Corporation Headquarters and Sales Office 22 Linnell Circle Billerica, MA 01821 TEL: (978) 667-8700 FAX: (978) 670-9001 e-mail: sales@sipex.com Sales Office 233 South Hillview Drive Milpitas, CA 95035 TEL: (408) 934-7500 FAX: (408) 935-7600
Sipex Corporation reserves the right to make changes to any products described herein. Sipex does not assume any liability arising out of the application or use of any product or circuit described hereing; neither does it convey any license under its patent rights nor the rights of others.
SP495
Quad Differential RS-485 Transceiver
(c) Copyright 2000 Sipex Corporation
6

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